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Don,

Congratulations on completing the project.

You seem to be getting a heck of a lot of power out of it for 5 v. Mine puts out 140mw with one BS170.

Re WSPR.

With this kit, there are two key factors in getting decoded: Exact time keeping, and being on frequency.

The first is easy really. Use an atomic clock such as this one:???

The other is more tricky - fiddly is a better word. My kit as built was set up with the standard settings of 125,000,000 and 14.097100 in the DDS clock setting and frequency. I got no spots at all. I tried measuring the DDS frequency but in the end incremented the transmit frequency 50 hz at a time until the wspr messages appeared on my own receiver and decoded. Beware that you will see many spurious signals because of overloading as you do this, but you will know when you hit the right one, because it will be much stronger than the others.???

I am currently running my DDS clock at 125,000,000 but my transmit frequency setting at 14.071480 which produces an actual output frequency of 14.097159, comfortably in the WSPR band. The cause of this disparity is that the DDS is not actually dead on 125mhz.

My time keeping without GPS was well off. The system clock in factory set up mode was 20mhz, but my clock is now keeping very good time day to day when set at 20,000,728. It has not moved at all in the last twelve hours tested against the bbc time pips.

These values will probably vary from circuit to circuit by small amounts because of component tolerance differences, but you could give them a try if you want.

As for GPS - mine won't work with a working gps module that works perfectly on the earlier kit with the same connections. If I solve that, I'll let you know how.

Good luck. You will have fun when it gets on frequency and on time.

G0BZB Tony

On 17 May 2013 09:13, <donald.vosper@...> wrote:

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Hi
Just assembled the kit with no problems.
Mastered the menu system and entered the data for wspr.
Getting 10V p-p, approx 250mW into a dummy load on 5V regulated supply with full set of BS170s. Although, as the instructions say , not a lot of difference with 5V.
It appears to be putting out a signal but after one or two sessions on 20M with a g5rv but no-one seems to be reporting my signals yet.
Perhaps there is something in the setting up that I have missed.
also I am not familiar with GPS modules. Is there one at a sensible price that is suggested for use with the kit?
Regards
Don m5aky

Don

I can second some of Tony's remarks, especially re variations from kit to kit.

Without GPS, my clock seems to keep good time without tweaking the 20MHz xtal frequency in the menu but I'll need to keep it running for a day to finally confirm that. Re WSPR frequency, on 20m, to transmit on 14097100, I've actually set my menu frequency to 14096850. This is due to the 125MHz xtal in the DDS not being quite on 125MHz. I have several of the Chinese DDS modules in other projects and they all have some frequency offset - usually several hundred Hz at 20/30m.

Operating the U2 using a GPS module seems to be causing some difficulties for Tony and me (any other reports please). The 406A GPS module seems to give the correct Maidenhead locator for my location but the time seems random. I've tried with the pull-up resistors as pull-up or pull-down (i.e connected to +5v or 0v). Both give a time display but it is different! In one case, the clock shows hrs, mins and secs but the secs increment in twos every second (trigging on both edges of the 1pps GPS pulses?). In the other case, the clock shows hrs and mins correctly but the secs are random and sometimes get corrected to the right value until the next 1 sec count when it goes random again. This presumably must be due to random variations in the interface voltage levels between the GPS and the ATMega? In the menu, I seem to need "Invert GPS" to be "on"

I hope some one can suggest a workaround for this soon as for me it's spoiling what is otherwise an excellent piece of work by Hans.

-- 

73

Barry, G8AGN